title: Hepatic antioxidant responses related to levels of PCBs and metals in chicks of three Arctic seabird species.
abstract: The efficiency of antioxidant defenses and relationship with body burden of metal and organic contaminants has not been previously investigated in arctic seabirds, neither in chicks nor in adults. The objective of this study was to compare such defenses in chicks from three species, Black-legged kittiwake (Rissa tridactyla), Northern fulmar (Fulmarus glacialis), and Herring gull (Larus argentatus), and the relationship with tissue concentrations of essential metals such as selenium and iron and halogenated organic compounds, represented by polychlorinated biphenyl (PCB). The results showed significant species-specific differences in the antioxidant responses which also corresponded with metal and PCB levels in different ways. The capability to neutralize hydroxyl radicals (TOSC-HO•) and the activities of catalase and Se-dependent glutathione peroxidases (GPX) clearly increased in species with the higher levels of metals and PCBs, while the opposite trend was observed for Se-independent GPX, TOSC against peroxyl radicals (ROO•) and peroxynitrite (ONOOH). Less clear relationships were obtained for glutathione levels, GSH/GSSG ratio, glutathione reductase and superoxide dismutase. The results showed differences in antioxidant efficiency between the species, and some of these defenses exhibited dose-response-like relationships with measured levels of selenium, iron and ΣPCBs. PCBs, selenium and iron levels were positively related to the responses of antioxidants with potential to reduce HO•/H₂O₂ (Se-dependent GPX, CAT and TOSC against HO•). However, direct causal relationships between antioxidant responses and contaminant concentrations could not be shown on individual level. Varying levels of metals and contaminants due to different diet and age were probably the main explanations for the species differences in antioxidant defense.
authors.affiliation: Akvaplan-NIVA AS, Fram center, 9296 Tromsø, Norway. marit@akvaplan.niva.no
authors.forename: Marit Nøst
authors.initials: MN
authors.lastname: Hegseth
authors.forename: Lionel
authors.initials: L
authors.lastname: Camus
authors.forename: Lisa B
authors.initials: LB
authors.lastname: Helgason
authors.forename: Raffaella
authors.initials: R
authors.lastname: Bocchetti
authors.forename: Geir Wing
authors.initials: GW
authors.lastname: Gabrielsen
authors.forename: Francesco
authors.initials: F
authors.lastname: Regoli
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001110:Arctic Regions; D030161:Avian Proteins / Q000378:metabolism; D001717:Birds / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D046091:Charadriiformes / Q000378:metabolism; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000633:toxicity; D016166:Free Radical Scavengers / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008670:Metals / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D013045:Species Specificity
chemical_list: D000975:Antioxidants; D030161:Avian Proteins; D004785:Environmental Pollutants; D016166:Free Radical Scavengers; D008670:Metals; D011078:Polychlorinated Biphenyls; D002374:Catalase; D005979:Glutathione Peroxidase; D005978:Glutathione; D019803:Glutathione Disulfide